Small scale substructure, collapse time and dynamical friction

Abstract

We solve numerically the equations of motion for the collapse of a shell of baryonic matter, made of galaxies and substructure of $10^6{M}_{\odot }÷10^9{M}_{\odot }$, taking into account the dynamical friction and the parameters on which it depends: the peaks' height ${\nu }_c$, the number of peaks inside a protocluster $N_{tot}$ multiplied by the correlation function $\xi (r)$ evaluated at r=0, the filtering radius $R_f$ and the core radius of the cluster of galaxies, r_0. We show how the collapse time of a shell of baryonic matter depends on those parameters.

8 pages and 4 figures,(Latex), To appear in "Dark and visible matter in galaxies and cosmological implications" eds. M. Persic and P.Salucci A.S.P. conference series